We have synthesize and ortho-carborane amino acid and plan to characterize the structural effects of its insertion into homopolyaminoacids such as poly-Alanine or poly-Phenylalanine. The secondary structure of these peptides should be helical, with perturbation by the carborane due to steric effects. Compaison with other beta-amino acid insertions such as ortho-aminobenzoic acid in these peptides will allow us to characterize specific helix-breaking interactions of the carborane. The change in helical structure caused by insertions of these types of amino acids will be initially determined using circular dichroism spectroscopy then by 2-D NMR. Modeling using MidasPlus will allow us to predict the structure of the modified polypeptides, and will aid us in selecting useful model compounds for further studies.